Analysis methods are discussed for polymer crystallization and melting with three different types of plots constructed by using fast-scan calorimetry and small angle X-ray scattering for the determination of the melting point T_M, heat of fusion ΔH_f and crystalline lamellar thickness d_c. Two of those plots are the well-known Hoffman-Weeks plot of T_M against crystallization temperature T_c and the Gibbs-Thomson (G-T) plot of T_M against 1⁄d_c in terms of the data-sets obtained in the primary stage of polymer crystallization. The third plot is a newly proposed Thermal G-T plot of T_M against 1/ΔH_f, both of which shows a logarithmic time evolution in the secondary stage with reorganization,i.e. lamellar thickening and crystal perfecting, of existing crystals formed in the primary stage. By utilizing those plots, the zero-entropy-production melting point T_M⁰, folding surface free energy σ_e, and a thickening coefficient γ can be evaluated. Obtained results are self-consistent and agreed with prior literature values. Temperature dependent σ_e suggests curved melting and crystallization lines of the G-T plot. Application of fast heating is essential for the quantitative analysis of the melting behavior of chain-folded lamellar crystals in a metastable state.